Did you see it on Monday? We received a LOT of stunning rainbow pictures!
Seeing those gorgeous colors up in the sky may have you wondering how they came to be in the first place. Of course, most of us know that you can't have a rainbow without a little rain. But what exactly is it about the rain that causes a rainbow to form afterwards? And why do we see rainbows at some times, but not others?
Let me explain it to you!
Steps to Form A Rainbow:
After a rain shower ends there are teeny tiny little rain droplets left hovering in the air! They are little spheres of liquid water, and there are millions of them. When the sun starts to come out from behind the clouds, its light shines on each of the tiny droplets.
Some of that light bounces right back off of the rain droplets. This is called reflection. Imagine looking into a clear, calm pool of water. You can see the bottom of the pool, but you can also make out your own faint mirror image at the water's surface. That mirror image is light reflecting back at you! It's faint because most of the light goes through the water with only a small bit being reflected. That's the same case with our tiny little rain droplets in the sky.
The light that does go through the water droplet bends, or refracts. If you put a straw into a glass of water you'll notice that the straw appears to have a kink in it right at the water's surface. There isn't actually any bend in the straw, it's just the refracting, or bending, of the light.
Something interesting happens when sunlight refracts inside of the water droplet: all of the different colors separate out. While sunlight appears white to us, it's actually made of all the different colors on the spectrum: red, orange, yellow, green, blue, and violet. When the white sunlight refracts inside of the raindrop, each of the colors is bent at a slightly different angle. This is called color dispersion, and it's the same thing that happens when you shine light through a prism.
3. Reflection- again!
When the light, now separated into all its colors, hits the edge of the drop, it bounces back. Think of it like a pool ball hitting the edge of a pool table- it comes back at an angle. From there, the colors of the rainbow are finally ready to escape the raindrop and put on their show!
4. Refraction.... again.
As the light crosses the water-air boundary, it bends once again before it finally exits the raindrop.
Fun Rainbow Facts!
- Rainbows are actually a full circle, but you only see the top half, which is why it looks like an arch. The bottom half is below the horizon, or in the earth.
- You can only see a rainbow when the sun is at your back. The circle of the rainbow forms around a point that is exactly opposite to the sun.
- You can only see rainbows either late in the day or early in the morning. During the middle of the day the sun is too high in the sky, and the opposite point that a rainbow would form around would be in the ground!
- Double rainbows happen when there are TWO reflections that occur within the raindrop. The colors of the double rainbow are reversed, with blue on the top and red on the bottom!